Prior U.S. Pat. No. 4,119,272 to Tidwell and the above-referenced prior application both disclose self-propelled row crop irrigators having transverse irrigation booms which are fed from an overhead hose reel through a tubing frame which also serves to support the massive hose reel on a wheeled undercarriage. The irrigator in the referenced pending application is self-steering by the action of a furrow following wheel and a trailing shoe which follows in the small grooves produced by the guidance wheel.
The present invention is a substantial improvement on the above prior art, both in terms of simplifying the guiding shoe steering arrangement and in providing an irrigator which is self-reversing at the ends of crop rows and which has two speeds of operation, a slow speed for irrigating and a faster speed for maneuvering beyond the ends of crop rows.
The essence of the present invention lies in a rockable frame supported on a wheeled undercarriage having a fulcrum for the frame which mounts a massive hose reel directly above the fulcrum. The frame is tubular to conduct irrigating water from the hose to a pair of transverse fore and aft irrigation booms on the frame and forming parts thereof. Traction driving units are bodily connected with the two booms and are raised and lowered when the frame is rocked on the axis of the fulcrum. One traction unit has a ground-engaging reversing mechanism and the two traction units are coupled through a drive shaft which enables both units to be operated by the slow speed drive means of the irrigator associated with one of the traction units. The other traction unit includes a higher speed drive means independent of the slower speed means.
Other features and advantages of the invention will become apparent during the course of the following detailed description.